1. Field
Methods and apparatuses consistent with exemplary embodiments relate to a television tuner module, and more particularly, to a television tuner module having two shield members that can shield external noise, and a broadcast receiving apparatus having the same.
2. Description of the Related Art
A broadcast receiving apparatus, such as a television, a video cassette recorder (VCR), a digital versatile disk (DVD) player, a set top box, etc., include a tuner, and can tune a desired frequency and receive a specific broadcast.
However, if the desired frequency is hampered by a transmitting frequency of a cell phone or another transmitter, the broadcast receiving apparatus may have poor reception sensitivity, as compared to when there is no disturbing signal. In a severe case, the broadcast receiving apparatus may not be able to tune to the desired frequency.
In general, the radio frequency immunity defined in the electro-magnetic susceptibility (EMS) item of the electro-magnetic compatibility (EMC) standard is a regulation regarding when a receiving frequency and a disturbing frequency are different from each other. Therefore, even if there is no special measures, EMS standard certification can be generally received.
However, as frequency use is increased, cases that different type of transmitters and receivers use the same frequency bands have been occurred.
For example, since cable broadcasts use a frequency band of 54 MHz-1 GHz and CMA phones or GSM phone use wirelessly a frequency band of 824 MHz-960 MHz, the frequency bands overlap.
In general, various countries use different frequency bands. However, when the transmission method (wired or wireless) is different, many frequency bands overlap, and thus mutual interference between frequency bands may occur.
FIG. 1 illustrates a general broadcast receiving system. A set top box 1 is disposed separately from an image display apparatus 3.
In this case, when a wireless communication device such as a cell phone 7 is used, a wireless frequency that is used for indoor and outdoor wireless communication may be interfered with by a broadcast signal that enters the set top box 1.
In FIG. 1, an external antenna 6 is connected with the set top box 1 by a coaxial cable 4. An amplifier 5 may be disposed between the antenna 6 and the set top box 1, if necessary. The cell phone 7 may be an LTE phone for fourth-generation communication.
FIGS. 2 to 4 are spectrums illustrating a case that a wired broadcast frequency is disturbed by a disturbing frequency, such as a wireless frequency.
In FIG. 2, a waveform D of an channel N indicates a spectrum of a desired receiving broadcast frequency. In FIG. 3, a waveform E indicates a disturbing frequency that is going to be overlapped with the wired broadcast frequency. FIG. 4 illustrates a spectrum when the disturbing frequency enters the wired broadcast frequency, and thus the waveform D is overlapped with the waveform E.
As described above, when a signal received by the broadcast receiving apparatus, such as the set top box 1, is overlapped with and hampered by a disturbing frequency, the disturbing frequency acts as noise with respect to the receiving signal, so as to degrade the receiving sensitivity. Therefore, the quality of displayed images or sounds may be deteriorated. When the noise is severe, the broadcast signal cannot be received, and as such displaying of the image is stopped.
Accordingly, a set top box that can prevent a broadcast frequency from being interfered with by a wireless frequency being used for a wireless communication is desirable.